Major goals of this program are to investigate, ultimately design and fabricate rectenna based systems to perform detection, communications, imaging, harvesting and control of high frequency electromagnetic radiation. We concentrate largely on the part of the spectrum that is not typically accessible with standard optical techniques or radio frequency (RF) electronics. In other words, we penetrate the ‘in-between’ Terahertz region with the goal of making it an accessible part of the spectrum. The rectenna is a novel combination of a micro-antenna and a tunneling metal-insulator-metal (MIM) diode. This combination allows for conversion of electromagnetic radiation in the terahertz frequency range (AC) directly into direct current (DC).
We develop a detector capable of working in the tens of terahertz frequency range. This type of detector bridges the gap between traditional RF detectors (<100GHz) and optical photodetectors (>1000THz). Such a detector can be used for transmitting data at very high speeds since the communication bandwidth will be several terahertz. Further, using nano-imprint technology, the infrared rectenna based detectors can be made very cost effective – even more than traditional optical detectors that require very low defect density wafers for manufacturing.
We use the rectenna technology to develop an imager in the terahertz (THz) range approximately between 3 and 30 THz (long to mid-range infrared). Infrared (IR) range THz imagers based on the rectenna principle can be used in night vision goggles and infrared cameras. Using low noise ROICs along with rectenna based IR detectors, we develop IR imagers that operate at speeds that are much higher than IR imagers that are currently available.
We also apply the rectenna technology to developing the capability of transferring and storing energy remotely. We build a prototype where electromagnetic energy in the THz range can be directed to a remote rectenna system. The rectenna system then converts the EM radiation into DC electrical energy.
A schematic of a rectenna based IR energy harvesting system
Illustration of combined solar panel-rectenna-battery structure for wideband energy harvesting and storage.
Schematic of the rectenna circuit that is used for detailed power and efficiency analysis.
Equilibrium energy band diagram for the symmetrical (LEFT) and asymmetrical (RIGHT) M-I-M structure.